The invention relates to an arrangement and to a method for detecting air ingredients, preferably for detecting air ingredients in buildings and vehicles.
For detecting air ingredients different embodiments are known, where metal-oxide gas sensors are used that are suitable for detecting airborne pollutants.
There are solutions that are suitable for particular lightly volatile substances (VOC) respectively, e.g. for car exhaust gases only. Up to now, there are no systems that are able to cover all of these ranges in order to control, for example, an air conditioning for rooms or to ventilate vehicle cabins in line with a pollution. As for many applications in vehicles the possible air flow rate is incessantly decreased, the known solutions fail these requirements.
For ventilating vehicles by a sensor controls there are known solutions from the late seventies that control the air condition by means of semiconductor gas sensors.
Because of severely changing ambient conditions as temperature, moisture or other influences, e.g. dust, relative levels are used for open or closed loop control. It would be desirable to have so-called artificial noses by which car exhausts as well as different smells can be detected such that the sensor can be used both indoors and outdoors and a sensor-internal monitoring of acting layers take place.
New developments in the area of semiconductor gas sensors, e.g. array structures, multichips and the like, enable to construct artificial noses that make it possible to much better cover the chemical space of attributes and to better copycat the properties of odor-guided sense organs by means of neuronal networks. Using this system it is possible to detect smallest concentrations in the ppb magnitude (e.g. inside a vehicle) as well as high concentrations in the ppm magnitude (e.g. outdoors). Besides, the drift is smaller than for single sensors, because no superimposed signals result from present gases. A disadvantage of this otherwise very advantageous design is its price, because several sensors and a multitude of electrical contacting wires are needed.